Is reglan da same as phenergan or promethazine?

No Reglan is not the same as Phenergan (promethazine) - although they both can be used to treat nausea and vomiting.

Reglan (metoclopramide) increases muscle contractions in the upper digestive tract. This speeds up the rate at which the stomach empties into the intestines.
Reglan is used short-term to treat heartburn caused by gastroesophageal reflux in people who have used other medications without relief of symptoms. It is also used to treat nausea and vomiting.

Phenergan (promethazine) is an antihistamine. It is used to treat allergy symptoms and also prevents motion sickness, and treats nausea and vomiting or pain after surgery. It is also used as a sedative or sleep aid.

https://www.drugs.com/reglan.html
https://www.drugs.com/phenergan.html